Multicylinder refrigerating machine



OGL 25, 1949- F. l.. VAN wEENEN 2,486,081

MULTICYLINDER REFRIGERATING MACHINE Filed Sept. 13, 19.45

[NVE/VIER Few'vc/.scw anat-aras Mm' WAZ/v5 Arran/vnf Patented Oct. 25,1949 MULTICYLINDER REFRIGERATING MACHINE Franciscus Lambertus vanWeenen, Eindhoven, Netherlands, assignor to Hartford National Bank &Trust Co., Hartford, Conn., as trustee Application September 13, 1945,Serial No. 616,093 In the Netherlands July 27, 1944 Section 1, PublicLaw 690, August 8, 1946 Patent expires July 27, 1964 In addition torefrigerating engines of the type in which the heat is conducted away bymeans of a gas which passes from the gaseous state into the liquid stateand vice versa there are also refrigerating engines in which the heat isconducted away by means of a gas which remains in the same physicalstate. In the latter type of machine the gas is successively expanded,thus storing heat, and compressed, thus evolving heat, this heat beingthen conducted away by a customary cooling-agent, such as water or air.This thermodynamic cycle is performed in an engine in which the gas isenclosed in a space of Variable volume in which or in open communicationwith which there is a part intended for heat transmission from themedium to be cooled to the gas in the engine, a regenerator and inaddition a part intended for the transmission of heat from the gas inthe engine to the said coolingagent, this last mentioned part also beingin open communication with a second space of variable volume. The partof the engine intended for transmission of heat from the medium to becooled 'tothe gas in the engine will be referred to hereinafter as theheater; the part intended for heat transmission from the gas in theengine to the cooling-agent as the coolerf The space of variable volumeadjoining the heater will be referred to hereinafter as the heatedchamber and the space adjoining the cooler as the cooled chamber.Between the variations in volume of the heated and the cooled chambersthere exists a phase difference such that the gas is compelled toperform the above-described cycle. Refrigerating engines of this kindare known for example from Zeuners Technische Thermodynamik, volume I.These refrigerating engines may be referred to as closed cycle enginessince an 'possible for the cooler to be omitted. n this case the gas isconducted away from the cooled chamber to the openair and for thefollowing cycle of operation a fresh supply of gas, in the particularcase air, is drawn in.

The present invention relates solely to refrigthe working mediumcirculates in the above described compartments in an unvaried physicalstate, i. e. according to the standard practice, in the gaseous state. Aknown form of such refrigerating apparatus is constructed to comprise asingle thermodynamic cyclic process, so that to increase the engineoutput, the dimensions of the compartments in vwhich this cycle ofoperation takes place, i. e., in this particular case, in the cylinders,as well as of the members that influence the volume of the heated andcooled chambers; all must be increased.

According to the present invention, a refrigerating engine of the abovedescribed type is constructed to comprise more than one cycle ofoperations which are performed in more than one cylinder. Each of thesecylinders contains a double acting piston, one of whose faces acts uponthe heated chamber and the other of which acts upon the cooled chamber.In order to obtain the necessary successive expansion and compression ofthe gas in each of the thermodynamic circuits, the heated chamber ofeach cylinder is connected to the cooled chamber of another cylinder,and the pistons of these cylinders are moved out of phase with eachother.

By employing a single double acting piston in each of the cylinders, asingle drive will suffice for each, in contradistinction to the knownonecylinder-engine in which there are always required two piston bodiesmoving with a relative phase-displacement. The two piston faces whichtogether influence the volume of a single cyclic process and hence mustmove with a given phasedisplacement relative to each other, are ofnecessity housed, in a multi-cylinder-engine, in two differentcylinders. For each separate cycle of operation the heated chamber isthus enclosed in a cylinder different from that in which the cooledchamber is enclosed. This, however, introduces the advantage that theconstruction of the moving engine parts is considerably simpler thanwith the one-cylinder-engine, having a single cycle of operation eachcylinder now requiring a single crank and connecting rod or else asingle connection to a swash plate mechanism.

According to the invention, the two piston faces which in a singlecylinder influence the volume of a heated chamber and of a cooledchamber are arranged on either side of a single piston body. In thismanner, the space in the cylinder on either side of the piston isutilised so that it is necessary for the piston rod to be taken throughthe cylinder wall by means of a customary stuiiing erating engines ofthe kind described, in which box packing.

In order that the invention may be clearly understood and readilycarried into effect it will now be set out more fully .with reference tothe accompanying drawing, in which an embodiment of the invention isillustrated by way of example.

The single figure in the drawing is a diagrammatic view of arefrigerating machine which works on the principle mentioned before andin` of the cylinders is surrounded by a heater 35, l

a regenerator |36 and a cooler |31, which are traversed by the gasenclosed in the cylinder. The heat is supplied from the medium to becooled, for example the air in a refrigerating cell or in a refrigeratorby means of a set of ribs |52 surrounding the heater on the outside. airto be cooled is in thermal contact with the ribs |52 of all of the fourcylinders and transmits the heat to the said ribs. This heat istransmitted by the heater |35 to the gas in each of the cycles ofoperation. After absorption of the heat, the gas is compressed by themovement of the piston, with the result that the temperature rises. 'Ihehotter gas comes into contact with the cooler |31 and transmits the heatthrough this cooler to the cooling water enclosed. in the jacket |53.This jacket with cooling water surrounds the coolers of all of the fourcylinders together so that a single cooling-water supply and a singledischarge pump are provided.

All the ribs |52 are provided on the heads of the four cylinders |3|,|32, |33 and |34. This means therefore that the top of the engine, thatis to say, that part which is remote from the crank-shaft side, becomescold when the engine is in use and serves for cooling of the medium tobe cooled. It is for example, possible to arrange these fourcylinder-heads in the chamber to be cooled itself and to arrange thatthe remaining part of the engine protrudes from this chamber. Theregenerators |36 are accommodated in the wall of the chamber to becooled and thus form part of the thermal insulation of this chamber. Itis also possible to arrange the whole of the engine in the chamber to becooled and to blow the air to be cooled into this chamber by means of afan so as to pass between the ribs |52. Although it is theoreticallyequally possible to arrange that each cylinder is so constructed thatthe portion which is cold when the engine is in use is arranged at thebottom of the cylinder, the construction as outlined is nevertheless tobe preferred for the above-mentioned reasons.

As shown in the figure of the drawing, the cooler |31 of the cylinder|3| is connected by means of a pipe |54 to the space under the piston inthe cylinder |32. Similarly the coolers of the cylinders |32, |33 and|34 are connected by means of the pipes |55, |56, |51 to the spacesbelow the pistons -in the cylinders |33, |34 and 3| respectively. Thespace above each piston communicates directly with the heater |35 whichsurrounds the cylinder concerned. A heated chamber |90 together with theheater |35, the

egenerator |36 and the cooler |31 of a cylinder,

" |3|, and with a cooled chamber |93 in a The further cylinder, say |32.forms an enclosure in which the gas is compelled to perform thethermodynamic cycle described. The volume of this enclosure isinfluenced by two different piston faces, to wit the upper surface |9|of a piston in one cylinder and the lower surface |92 of a piston in theother cylinder. These pistons are connected to two cranks which in thepresent case are at an angle to one another. The respective piston faces|9| and |92 consequently move with a given phase dierence, the variationin volume of the space |93 being, in the direction of rotation of theengine indicated by the arrow ggg, in advance with respect to that ofthe space The general operation of the refrigerating engine is asfollows. The compartments of each cylinder enclose a quantity ,of gas.After the piston has reached the top dead centre position, as is thecase in the cylinder 3|, and ben gins to descend, expansion occurs inthe space above the surface |9| with the result that the gas containedtherein cools. This permits of the said gas absorbing heat via theheater |35 and. the ribs |52 from the medium to be cooled. Upon asubsequent increase in volume of the cooled chamber |93 this gas, whichhas absorbed heat, flows through a regenerator |36 and a cooler |31 tothe cooled chamber |93. In this chamber compression then occurs, so thatthe temperature of the gas rises. At the same time the gas is returnedthrough the cooler |31 to the heated chamber |90. In the cooler |31,however, the gas transmits the heat to the surrounding cooling liquid inthe jacket |53 and thus returns at a lowertemperature,into the heatedchamber |90. Again, expansion occurs in this chamber so that the gascools and is again capablefof absorbing heat, and so forth. This gasVmovement is performed in two different cylindersby two different pistonfaces moving with phase'displacement. In any given cylinder a portion oftwo cycles of operation is performed. Now, the connection between theindividual cylinders is such that 'the portions of the two cyclicprocesses that take p'lace in one cylinder are performed with a relativephase displacement of The two piston faces which are required toinfluence these portions of two cycles of operation may therefore becoupled together at any time. In the embodiment shown these surfaces,|9| and |92 respectively, are arranged on either side of the piston body|49.

The four cylinders are arranged on a common crank case |58 sealed offfrom the surroundings in a gas-tight manner. The crank-shaft |42, withthe four cranks placed therealong so that adjacent cranks are at anglesof 90 with one another is supported within this crank-case by twobearings |43 and |44. This crank-case also contains an electric motor|45 which drives the refrigerating engine and the current supply leads|46 therefore are taken through the wall of the crank-case in agas-tight manner. The cylinders are also sealed off from the crank-casein a gastight manner, the piston rods |50 being taken in a gas-tightmanner through stuing boxes |48 provided in the bottom surfaces of thecylinders.

For the arrangement of the various connecting channels from |54 to |51inclusive between the cylinders and the coolers it is desirable thatthese cylinders be arranged as close together as is possible. Thearrangement of four cylinders in line, as shown in the gure, has theadvantage that a single crank-shaftsuiices. Three of the four connectingchannels, to wit |54, |55 and |56 may be short, but the connectingchannel |51 between the first cylinder |3| and the cooler |31 of thefourth cylinder |34 is comparatively long. An improvement can beobtained by arranging the cylinders in pairs in the shape of Vs formingan angle of 90. In this case, a crank-shaft with two cranks suffices.each crank being engaged by two connecting-rods. The simplest form ofconstruction is that in which the cylinders are arranged in a square andthe pistons are driven through the intermediary of a swash platemechanism. In the latter case, the four connecting channels may be veryshort. Moreover, in this case the construction of each cylinder isidentical and this is advantageous particularly in connection with massproduction methods.

The cycle of events of the confined gas in the operation of therefrigerating machine of the present invention will now be set forth indetail to include the relationship between the piston position, confinedgas pressure and gas volume for every 90 of crank-shaft rotation start--ing from the position shown in the figure.

As the shaft |42 rotates 90 in the direction of the arrow |59, it willbe seen that the piston in cylinder |3| will leave the 'top dead centerposition shown in the figure to move downwardly to a position midway ofthe ends of said cylinder; the piston in cylinder |32 will move to thetop dead center position in said cylinder |32; the piston in cylinder|33 will move to a position midway of the ends of said cylinder |33; andthe piston in cylinder |34 will move to the bottom dead center positionin said cylinder |34. During the rotation of the shaft |42 as statedabove and the concomitant movement of the pistons as likewise set forthabove, the gas conned between face |9| of the piston in cylinder |3| andface |92 of the piston in cylinder |32 is expanded; the gas confinedbetween the faces |9| and |92 of the pistons in cylinders |32 and |33,respectively, is displaced in a substantially constant volume from theheated chamber |90 of cylinder |32 to the cooled chamber |93 of cylinder|33; the gas confined between surfaces |9| and |92 of the pistons incylinders |33 and |34, respectively, is compressed; and the gas confinedbetween surfaces |9| and 92 of the pistons in cylinders |34 and |3|,respectively, is displaced from the cooled chamber |93 of cylinder |3|to the heated chamber |90 of cylinder |34.

As the shaft |42 rotates through the next 90 in the direction of thearrow |59, the piston in cylinder i3! approaches bottom dead centerposition; the piston in cylinder |32 moves downwardly to a positionsubstantially midway of the ends of said cylinder |32; the piston incylinder |33 approaches top dead center position; and the piston incylinder |3|, moves upwardly to a position midway of the ends of saidcylinder |34. As the pistons move as just described, the gas confinedbetween surfaces |9| and 92 of the pistons in cylinders |3| and |32,respectively, is displaced in a substantially constant volume from thecooled chamber |93 'ln cylinder |32 to the heated chamber |99 incylinder |3|; the gas confined between surfaces |9| and |92 of thepistons in cylinders |32 and 33, respectively, is expanded; the gasconfined between surfaces |9| and |92 of the pistons in cylinders |33and |34, respectively, is displaced from the "heated chamber |99 ofcylinder |33 to the cooled chamber |93 of cylinder |34; and the gasconined between the surfaces |9| and |92 of the pistons in cylinders |34and 3| respectively, is compressed.

In the next of rotation of shaft 42 in the direction of the arrow |59,the piston in the cylinder |3| moves upwardly to a position midway ofthe ends of said cylinder, the piston in the cylinder |32 movesdownwardly to the bottom dead center position; the piston in cylinder|33 moves downwardly to a position midway of the ends of said cylinder;and the piston in cylinder |34 moves upwardly to the top dead centerposition therein. As a, result of the above movement of the piston, thegas confined between surfaces |9| and |92 of the pistons in cylinders|3| and |32, respectively, is compressed; the gas confined betweensurfaces |9| and |92 of the pistons in cylinders |32 and |33,respectively, is displaced in a substantially constant volume from thecooled chamber 93 of cylinder |33 to the heated chamber of cylinder |32;the gas confined between surfaces |9| and |92 of the pistons incylinders |33 and |34, respectively, is expanded, and the gas confinedbetween surfaces |9| and |92 of the pistons in cylinders |34 and |3|,respectively, is displaced from the heated chamber |90 in cylinder |34to the cooled chamber |93 in cylinder |3|,

When shaft |42 rotates the next 90 to approach the position shown in thefigure and so complete the cycle of operations, the gas conned betweenthe surfaces |9| and |92 of the pistons in cylinders |3| and |32,respectively, is displaced in a substantially constant volume from theheated chamber |90 of cylinder |3| to the cooled chamber |93 in cylinder|32; the gas confined between the surfaces |9| and |92 of the pistons incylinders |32 and |33, respectively, is compressed; the gas confinedbetween the surfaces |9| and |92 of the pistons in cylinders |33 and|34, respectively, is displaced from the cooled chamber |93 of cylinder|34 to the heated chamber of cylinder |33; and the gas confined betweenthe surfaces |9| and |92 of the pistons in cylinders |34 and |35,respectively, is expanded. After the position shown in the figure isreached, the cycle of operations described above is repeated.

What I claim is:

1. A multi-cylinder refrigeration machine comprising a plurality ofcylinders cooled at one end and heated at the other end, within each ofwhich is a piston connected to a common source of motive power andacting upon an incondensable gas, said cylinders being partiallysurrounded by a jacket through which the medium to be cooled passes, aconduit for passing the gas in a closed cycle of operation between thetop of one cylinder and the bottom of another cylinder, said conduitcontaining means for exchanging heat with the gas and being partiallysurrounded by a jacket through which iiows a cooling fluid fordissipating a portion of said heat.

2. A multi-cylinder refrigeration machine comprising a series of fourcylinders in line, each cooled at one end and heated at the other end,within each of which is a double acting piston connected to a commonsource of motive power by means of a common crankshaft, each of saidpistons moving 90 out of phase with the adjoining pistons and actingupon an incondensable gas, conduits for passing the gas in a closedcycle of operation between the top of each of the first three cylindersand the bottom of the cylinders next in line, another conduit forpassing the gas in a closed cycle of operation between the 2,486,081 8:gp of the fourth cylindelilanfd the bottoltsc! 15h45 w' REFERENCESCITED st cylinder in line, eac o sa d cond containing means forexchanging'heat with the B88 mh ftohniosvgtzlfferences are of record inthe and being partially surrounded by a jacket through which flows acooling uid for dissipat- 5 UNITED STATES PATENTS ing a portion of saidheat. Number Name Date 252,921 Allen Jan. 31, 1882 FRANCISCUS LAMBERTUS"N WEENm- 1,240,862 Lunagaard sept. 25, 1917

